Quantitative Aptitude Notes Part 3(PERCENTAGE)

What is percentage? Percentage is a fraction or a numerical expression or a ration with 100 assumed as denominator. So we can represent 1 percentage as 1%.

Points to be remember-

1 = 100%

1/2 = 50%

1/3 = 33%

1/4 = 25%

1/5 = 20%

1/6 = 16%

1/7 = 14%

1/8 = 12%

1/9 = 11%

1/10 = 10%

1/11 = 9%

1/12 = 8%

1/13 = 7%

If the price of a commodity increases by R%,then the reduction in consumption as not to increase the expenditure is =%

If the price of a commodity decreases by R%,then the increase in consumption as not to decrease the expenditure is=%.

Let the population of a town be P now and suppose it increases at the rate of R% per annul, then:

Population after n years =P (1+R/100)n

Population n years ago =

Let the present value of a machine beP. Suppose it depreciates at the rate of R% per annul, then :

Value of the machine aftern years =P(1-R/100)n

Value of the machinen years ago =

IfA isR% more thanB, thenB is less thanA by=%

IfAisR% less thanB, then B is more thanA by= %.

Percentage Type1 Shortcut TricksExample: If the difference between 45% of a number and 3/5th of that number is 18. What is the number?Solution: Let the number be a . Then a x 45% – a x 3/5 = 18 a x 45% – a x 60% = 18 ∴( 60% = 3/5 ) a x 15% =18 a = 100×18 = 1800/15 = 120Tricks: we know 3/5 = 30% 45% – 30% = 15 % 15% = 18 = 120

Percentage Type2 Shortcut TricksExample: Sahil work in shop and his 30% of income is Rs.1800 .Find the 65% of his income and also find the 1 / 5 of Sahil’sincome.

Solution:30% = 1800 So, 65% = 1800 x 65 / 30 = 3900

Shortcut Trick:1800 x 65 / 30 = 3900.

Example: Raj spend his money from his saving in different way that is he spends 30% on travel,10% on food,15% on wages and 22% on purchase a bike and after that all expenditure he saved 4600.Find the how much he spent on bike.Solution: Let the total income of Raj=X.